Mariner 75HP Rectifier?

[njbadboy]

Hello all, I have a 17' Mark Fisher Marsh Hawk 3V with a 75HP Mariner OB. I'm planning on a trip down to Smith Mountain Lake next month, so I took the boat out on the river and noticed that the Tach is not working and the volts remain around 12.6V at all times. As I rev the motor, the volts do not change. I have a volt meter in the dash and the fish finder also can display volts.

I understand that this was a common problem with the Mariner OB in my range of year. Also I was told that usually if the rectifier is bad, that stator will follow. I've had the boat four years now (bought from original owner) and it been on the water about 4 times, and the Tach never worked.

Is this something that a person can repair with some mechanical knowledge? How do I test the stator or is there an easier way to tell if it went bad, without taking everything apart?

The motor starts without a problem, always on charger, and runs as if its new. I do not want to screw anything up since it runs so well!

Is the rectifier on top of the motor, silver box with two red wires, two yellow wires and a grey wire?

Also I guess there are two rectifiers for this motor, a 9 amp and a 16 amp? How can I determine which one I have? There are these numbers on the size of that silver box (815279 1 with 2590 underneath of them)

Also I believe I have a 1991 Mariner. Serial # 0D037684. Its a 3 cylinder with oil injection and electric start.

The dealer price the part at $150-170, but I've seen them on ebay between $65-$135. Anyone recommend somewhere that a fair price and reliable?

Thanks for any help in advance!!

Jeff

 

[Maxz695]

Re: Mariner 75HP Rectifier?

I believe not sure that this is a four stroke. The square box in the last picture is your voltage regulator. When these get old the poly fill can crack and let moisture into them creating a short at times and not at others. This drives people nutts trying to figure out what is wrong with there engine and test after test shows it to be good. With the four stroke I,m not sure it has a rectifier as i,m very limited in my knowledge on four stroke engines. If someopne can confirm there is not a rectifier. then I would think that would need to be replaced

 

[Faztbullet]

Re: Mariner 75HP Rectifier?

This is a 2 stroke engine and the part number is 815279 for reg/rectifer. Check it first before you purchace on as it could be a bad connection or loose wire. You can amazon it for best price but you can get it here on iboats also.

 

[njbadboy]

Re: Mariner 75HP Rectifier?

No the motor is definately a 3 cylinder 2 stroke.

After posting the question on the board, I found the numbers on the side of the recetifier *815279-1, which is a 16 amp recetifier.

I will check the connections.....I imagine that I need to remove the oil reserve tank in order to locate the wires, I haven't gone to far than removing the cowl and taking the pictures.

Have you heard the stator going bad if the recetifier goes? Is there an easy way to check the stator without removing it?

Thanks guys for the help

Jeff

 

[njbadboy]

Re: Mariner 75HP Rectifier?

Hey, I checked what I could with a multimeter.

In checking the volts at idle its about 12-12.4. Volts don't increase when increasing RPM. I checked this at the battery

I disconnected the gray wire for the tach from the rectifier and it read between 7.5-8.0 volts at idle.

In following the manual, I check the stator, using the two yellow wires, with engine off, and got a reading above 100k, I think 191K (thats even if I did it correctly)

I'm pretty sure the rectifier is bad; but not sure about the stator. All the wiring checked good.

Even though the engine is a 1991, it is super clean and probably has about 50-60 hours of use. I knew the previous owner and he estimated about 40-50 hours. I might have put ten hours on it at most myself over the last few years since I mostly use the trolling motor to fish.

So I'm thinking about just ordering the rectifier....I leaving for a trip to Smith Mountain in two weeks and the shop cant get it in before I leave.

Thanks for any help that you can offer.

Jeff

 

[Bill3434]

Re: Mariner 75HP Rectifier?

Hey, I checked what I could with a multimeter.

In checking the volts at idle its about 12-12.4. Volts don't increase when increasing RPM. I checked this at the battery

I disconnected the gray wire for the tach from the rectifier and it read between 7.5-8.0 volts at idle.

In following the manual, I check the stator, using the two yellow wires, with engine off, and got a reading above 100k, I think 191K (thats even if I did it correctly)

I'm pretty sure the rectifier is bad; but not sure about the stator. All the wiring checked good.

Even though the engine is a 1991, it is super clean and probably has about 50-60 hours of use. I knew the previous owner and he estimated about 40-50 hours. I might have put ten hours on it at most myself over the last few years since I mostly use the trolling motor to fish.

So I'm thinking about just ordering the rectifier....I leaving for a trip to Smith Mountain in two weeks and the shop cant get it in before I leave.

Thanks for any help that you can offer.

Jeff[/QUOTE

A rectifier is a one way electrical valve converting A/C to D/C. If you get a low ohm reading on a connection reverse the leads and you should get a very high reading or infinity. If you get high or low readings both ways your diodes are shot. You should be able to test the voltage from stator by checking the voltage prior to the rectifier just make sure you have your volt meter set for A/C and start with a high voltage setting, then work your way down. The voltage will depend on the number of windings in your stator, you will have to get the specifications to know if it is working properly.

PS. I hope you are checking the rectifier disconnected from all power sources. Obtaining ohms on a live circuit is not good.

 

[halmc]

Re: Mariner 75HP Rectifier?

If you have continuity through the stator, chances, are very good that it is unhurt. The output of the stator is an AC signal. If you wanna measure it, use an AC scale on your multimeter. But a continuity check is good enough, and a voltage check on an unloaded, floating AC alternator will get you crazy readings and it could provide you with a trouser-soiling shock.

Since I have a rectifier on order, ($27, shipping included, ebay item #110938299796) I join others in noting that it's not all that robust.

When you're all done, measure the voltage across the battery posts with the engine set at a high idle -- 2000 rpm or so. You should show something in excess of 13VDC. Don't measure it anywhere else: the battery posts are where the rubber meets the road, allegorically speaking.

Lastly, if you leave for Smith Mountain intending to use energy from your battery only for the engine, and if you have a good battery, the electrical demands of the engine are very modest if you take it real easy on the tilt/trim button. You'll make it just fine w/o a rectifier. For now.

 

[oldman570]

Re: Mariner 75HP Rectifier?

As the others have stated the recifiter is probbly the only thing bad at this point and needs to be replace ASAP as damage to the stator could happen with contindued use of the motor as is. You can disconect the yellow wires from the recitifer at the plugins or terminal strip and insulate the ends and use it for a short time, but the recitifer should be replaced. When going any distantance from home I always take a small charger along just incase of any trouble. JMO
Oldman570

 

[Georgesalmon]

Re: Mariner 75HP Rectifier?

In your first post you said the tach was not working. That could be an indication the the stator is bad. The tach signal comes from the stator. Since you have put an ohm meter on the stator and it has some resistane it could be OK. I don't know if you did this with the yellow wires disconnected from everything else though.

 

[njbadboy]

Re: Mariner 75HP Rectifier?

Okay I tested everything again, with the battery disconnected, using a multi meter. I was not sure what setting, but I used 200k. I followed these steps:

Check rectifier first using an ohmmeter, preferably with a diode/continuity function:

Yellow wire 1:
Red lead: red wire; black lead: yellow wire = no continuity (or "high" resistance)
Red lead: yellow wire; black lead: red wire = continuity (or "low" resistance)
Red lead: yellow wire; black lead: case ground = no continuity ("high")
Red lead: case ground; black lead: yellow wire = continuity ("low")

Then repeat these tests with yellow wire 2.

(All these tests to be done with rectifier installed and all wires attached to motor. "Lead" means the lead from the meter))

If you pass all these tests, rectifier is good. If you fail any of them, rectifier is bad.


Results

Yellow #1 (200k setting 20m setting)

Step 1 45.4 .003
Step 2 44.3 .003
Step 3 59.3 .005
Step 4 59.2 .004


Yellow #2


Step 1 45.4
Step 2 44.3
Step 3 59.3
Step 4 59.1


If I understand correctly the rectifier is bad? I have no clue what the numbers mean or even if I used correct setting. I tried a lower setting, but no readings.

Did I do the test correctly and if so, it is the rectifier?

Thank you again!

Jeff

 

[Bill3434]

Re: Mariner 75HP Rectifier?

You kind of lost me on your on after you continuity test. You continuity test looks correct and your rectifier is ok. I just looked at your original post and your pics again. Given the size of the box it is most likely a rectifier and regulator all in one circuit which explains the price. Your voltage shouldn't increase very much with an increase in RPM's that is what the regulator does for you. High quality regulators you wouldn't/shouldn't see any increase; not likely to find those on an OB. It's hard to run you throught the checks through the internet darn near gotta be there. Oldman is correct though you don't need to be running that motor without the rectifier; recitfiers are a lot cheaper and easier to replace that a stator on a motor.

Okay I tested everything again, with the battery disconnected, using a multi meter. I was not sure what setting, but I used 200k. I followed these steps:

Check rectifier first using an ohmmeter, preferably with a diode/continuity function:

Yellow wire 1:
Red lead: red wire; black lead: yellow wire = no continuity (or "high" resistance)
Red lead: yellow wire; black lead: red wire = continuity (or "low" resistance)
Red lead: yellow wire; black lead: case ground = no continuity ("high")
Red lead: case ground; black lead: yellow wire = continuity ("low")

Then repeat these tests with yellow wire 2.

(All these tests to be done with rectifier installed and all wires attached to motor. "Lead" means the lead from the meter))

If you pass all these tests, rectifier is good. If you fail any of them, rectifier is bad.


Results

Yellow #1 (200k setting 20m setting)

Step 1 45.4 .003
Step 2 44.3 .003
Step 3 59.3 .005
Step 4 59.2 .004


Yellow #2


Step 1 45.4
Step 2 44.3
Step 3 59.3
Step 4 59.1


If I understand correctly the rectifier is bad? I have no clue what the numbers mean or even if I used correct setting. I tried a lower setting, but no readings.

Did I do the test correctly and if so, it is the rectifier?

Thank you again!

Jeff

 

[njbadboy]

Re: Mariner 75HP Rectifier?

Note....when I put the mutilmeter on the continuity setting and touched two leads together , the multimeter beeped,as it should have; however when performing the above test, there was never no sound indicating any continuity, so that's when I switched to the 200k ohm setting.

Shouldn't have I gotten the alarm to buzz during the test?

Jeff

 

[Georgesalmon]

Re: Mariner 75HP Rectifier?

(All these tests to be done with rectifier installed and all wires attached to motor. "Lead" means the lead from the meter))

If all the wires were still attached to the motor The readings might not mean anything. You must disconnect the wires from the motor to do a proper test.

 

[njbadboy]

Re: Mariner 75HP Rectifier?

Okay, so I disconnected all the wires from the rectifier to the terminal and disconnected the two yellow wires to the terminal from stator. I got no signal on continuity buzzer test or any other reading with ohm set at 200k.

 

[njbadboy]

Re: Mariner 75HP Rectifier?

I decided to remove the flywheel cover and check the wires the best I could without removing the flywheel. I see two separate sets of wires coming from underneath. One of the sets appears to have a red, black, white, and blue wires coming from stator closer towards back of motor. I found what to be a broken black due to the way it was went from factory.

I wonder of this is the root of the problem I'm having with not charging? Like I said prior the motor starts on first or second turn of key, and runs like a champ. Even at WOT, there is no bogging or missing.

I'll probably have take boat to shop now since I have reached my limitations. I am not famailair in removing the fly wheel and not sure if I were to, if I would screw up the timing or anything else.

It is possible to repair that one wire or does the stator now need to be replaced? Everything else in the boat works, such as the gauges, except for the tach.

Attached is a picture under the flywheel of the broken wire.

Thanks

 

[Dave1027]

Re: Mariner 75HP Rectifier?

Some motors don't use the black wire (ground) from the stator. What about the other end of the black? If you don't see the other end of the cut black then it's a safe bet the motor came that way. In other words, that cut off black from the stator is not the problem.

Does you motor have a regulator? I think it was an option.

 

[njbadboy]

Re: Mariner 75HP Rectifier?

I'm pretty sure the other end of the black wire is connected.

I do have a rectifier, that I thought was the problem and tried testing with a multimeter. See post above. One person to test with all wires connected, other than battery and another said to test with no wires connected. SO now that I did both, I confused more than ever.

I'm leaving in two weeks for fishing and the two marine shops can't get the boat in before hand.

 

[Dave1027]

Re: Mariner 75HP Rectifier?

I apologize for posting before reading the entire thread. It does look like you have a combo rectifier/regulator module. I think others already identified it as such. That said, you cannot test it with a diode test. If you do not want to pay for another module an option would be to simply replace it with a rectifier and go without regulation.

 

[Bill3434]

Re: Mariner 75HP Rectifier?

I should have thought about it sooner but a continuity check on a diode is not going to work. It may work on some diodes but I wouldn't bet on it. If you are sure that black wire is supposed to be connected fix it and see what happens. Dave is right it maynot have been used in that set up and not an issue. But you know what you have better than we do. DON'T GIVE UP YET!!!! You still got some testing left to do.

When testing Ohms (resistance) you never ever test on a circut that may be live, you may blow your meter. In ohms testing the power is provided by your meter. Since your system appears to be regulated you most likely have capacitors in the circuit which acts as a minituare battery which can be bad for your meter again. Testing you rectifier/regulator is difficult and hard to explain without a spec sheet. Lessons your learn will hep others.
Sorry for the late response but I had to work on my own boat.

 

[njbadboy]

Re: Mariner 75HP Rectifier?

I really appreciate the help everyone. The black wire that is broken is definitely connected to another terminal.

I had continuity with the two yellow wires from the stator, but none when each was grounded. The resistance, if was done correctly, was .001-.05. Specs call for .19-1.7

I have someone coming over later in the week that knows a lot more about motors and does side jobs, to help. I'm just wondering now that if it is the stator or trigger, not sure what wires go to what, instead of the rectifier. Unless the broken wire fried the rectifier??

I remember getting voltage from the gray tach wire, around 7.5-8v at idle.

I'll keep ya updated and hopefully I can get it done before I leave for fishing week!

Jeff